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  #1  
Old 05-06-2017, 12:40 PM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 947
Default Main Gear Axle

I'm hoping to find a builder with a main gear axle available, who could take a few measurements for me. My 12 is flying, and I hate to take things apart right now. Since they come in the finish kit, they are usually not installed until late in the fuselage build sequence. I need the axle flange dimensions, and the bolt pattern. You guessed it. I would like to see if I can make my own axle shims, and I want them to be full flange shims. The measurements, or a print would be fantastic. Just think of what dimensions you would need to make your own.
Thanks for your help

Tom
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  #2  
Old 05-08-2017, 07:48 AM
todehnal todehnal is offline
 
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Location: Kentucky Lakes area in KY
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Well. I decided to go ahead and remove my wheel pants and see if I could take some measurements. It was no problem. It looks like the axle base is 2" X 2" and the hole pattern has 1 3/8" center to center spacing, is located equal distance from the center and parallel on each side. I also took a measurement of the wheel camber. It measures a full inch from being perpendicular to the floor at the outside of the tire. Even with 2 aboard and full fuel, it still has a lot of camber, and my plan is to reduce that to a point where the tire will have a fully centered foot print at 1320 lbs............Tom
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1998- RV-9 tail kit, built and sold
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  #3  
Old 05-08-2017, 10:31 AM
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joedallas joedallas is offline
 
Join Date: May 2010
Location: Spring Hill Fl
Posts: 734
Default hard landing

Tom
I believe that the gear is stronger before it reaches the angle where the tires are vertical.
The gear needs to take up the force of a hard landing.
The tires need to get farther apart for the gear so spread.

On a hard landing the tires are not turning before touchdown, they have to slide sideways to let the gear absorb the load.

Interesting geometry

I would not change this without talking to the people at Vans.

my view

Joe Dallas

Quote:
Originally Posted by todehnal View Post
Well. I decided to go ahead and remove my wheel pants and see if I could take some measurements. It was no problem. It looks like the axle base is 2" X 2" and the hole pattern has 1 3/8" center to center spacing, is located equal distance from the center and parallel on each side. I also took a measurement of the wheel camber. It measures a full inch from being perpendicular to the floor at the outside of the tire. Even with 2 aboard and full fuel, it still has a lot of camber, and my plan is to reduce that to a point where the tire will have a fully centered foot print at 1320 lbs............Tom
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Last edited by joedallas : 05-08-2017 at 10:46 AM.
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  #4  
Old 05-08-2017, 10:44 AM
John-G John-G is offline
 
Join Date: Jan 2012
Location: Northeast Ohio
Posts: 685
Default

Hi Tom,

While building my RV-12 the EAA tech councilors consulted to do periodic inspections during the build gave me a suggestion that seems to have merit when doing the gear alignment.

The suggestion was to use two one foot square pieces of greased aluminum plate under each wheel when making the alignment measurements. The idea being, the wheels will be able to "slide" to their natural position based on the amount of weight applied to the gear.

I have not personally tried this method yet .... but the logic seems sound, so plan to give it a go when I get around to tweaking the gear.
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  #5  
Old 05-08-2017, 08:00 PM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
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Quote:
Originally Posted by John-G View Post
Hi Tom,

While building my RV-12 the EAA tech councilors consulted to do periodic inspections during the build gave me a suggestion that seems to have merit when doing the gear alignment.

The suggestion was to use two one foot square pieces of greased aluminum plate under each wheel when making the alignment measurements. The idea being, the wheels will be able to "slide" to their natural position based on the amount of weight applied to the gear.

I have not personally tried this method yet .... but the logic seems sound, so plan to give it a go when I get around to tweaking the gear.
This is a fantastic idea. Thanks for passing it on. I will definetly follow through with it before making any changes. ..... Tom
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2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
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  #6  
Old 05-08-2017, 08:18 PM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
Default

Instead of greased aluminum plate, how about wood sitting on 2 or 3 short lengths of 1/2" or 3/4" pipe?
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  #7  
Old 05-09-2017, 05:03 AM
todehnal todehnal is offline
 
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Location: Kentucky Lakes area in KY
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Yeah, I think the wood and pipe would work well also, with less cleanup. It may be a bit more challenging to get the mains up, and in place though
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2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
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  #8  
Old 05-09-2017, 08:44 AM
Richard@Langair Richard@Langair is offline
 
Join Date: Mar 2010
Location: Scappoose
Posts: 119
Default Actual hole pattern

The hole pattern is actually 1.370 center to center. Not 1.375. If you are going to be having the shims made at a shop that can measure that close it will make a big difference.
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  #9  
Old 05-09-2017, 11:00 AM
todehnal todehnal is offline
 
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 947
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Quote:
Originally Posted by Richard@Langair View Post
The hole pattern is actually 1.370 center to center. Not 1.375. If you are going to be having the shims made at a shop that can measure that close it will make a big difference.
Thanks Richard. I would not have expected the 1.370" measurement. I recall an earlier post about someone who had shims made and stated that the hole pattern was a bit off. My guess is that they used 1.375. I won't make that mistake............Tom
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2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
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  #10  
Old 05-09-2017, 02:04 PM
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Piper J3 Piper J3 is offline
 
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Location: Hinckley, Ohio
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Definitely keep us posted on this. It would be nice not to wear the tires so uneven.

Are you flying on pavement or grass?
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